S08 - Session O2 - Optimal planting density, effects on harvest time and yield

Authors: KC Shasteen, Joseph Seong, Simone Valle de Souza, Chieri Kubota, Murat Kacira *

An analysis was performed to identify the optimal planting density and time of harvest for a lettuce crop. Images of an experimental crop (cultivar Salanova) were taken to measure its Top Projected Canopy Area (TPCA). This area data was used to calculate size information about the lettuce and plot it against time. Head size information was then combined with a hexagon tiling algorithm to find the range of possible planting densities (in plants m -2 ) that could accommodate plants of progressive sizes. Finally, a model was used to make predictions about the mean mass (g head -1 ) of a head of lettuce over time. The analysis then combined this information to generate a yield rate (g m -2 day -1 ) function. By finding the maximum of this function, the optimal harvest time in days after transplant was discovered. Further analysis explored the potential effects of allowing the canopy to crowd, with potentials to improve yield rates. The effects of crowding on the time of optimal yield rate were also evaluated. This presentation will provide information on the methodology used in the study and results obtained on optimal planting density, effects on harvest time, and yield.